Broad category defining practitioners who help prevent and treat illness by promoting healthy eating habits, scientifically evaluating diets and suggesting modifications. They may also assess the nutritional needs of patients, develop and implement nutritional care plans.

A registered dietician (RD) is a food and nutrition expert who has successfully completed a minimum of a bachelor's degree at a US regionally accredited university or college and course work approved by The American Dietetic Association (ADA); an ADA-accredited or approved, supervised practice program, typically 6 to 12 months in length; a national examination administered by the Commission on Dietetic Registration; and continuing professional educational requirements to maintain registration. Source: The American Dietetic Association. Becoming a Registered Dietitian - a food and nutrition expert. Chicago, IL: The American Dietetic Association, July 1997.

A specialist in adapting and applying food and nutrient knowledge to the solution of food and nutritional problems, the control of disease, and the promotion of health. Nutritionists perform research, instruct groups and individuals about nutritional requirements, and assist people in developing meal patterns that meet their nutritional needs; (2) A nutritionist is someone who has completed undergraduate and/or graduate training in the discipline of nutrition without necessarily meeting the academic and experience requirements to qualify for the Registered Dietitian designation. Source: (1) Rhea, Ott, and Shafritz, The Facts On File Dictionary of Health Care Management, New York: Facts On File Publications, 1988.